Premium
Electromyographic evidence of subclinical myopathy in hypertrophic cardiomyopathy
Author(s) -
Karandreas Nikos,
Stathis Pantelis,
Anastasakis Aris,
Rigopoulos Angelos,
Piperos Panayiotis,
Theopistou Artemis,
Stefanadis Chris,
Toutouzas Pavlos
Publication year - 2000
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/1097-4598(200012)23:12<1856::aid-mus9>3.0.co;2-t
Subject(s) - electromyography , hypertrophic cardiomyopathy , myopathy , motor unit , skeletal muscle , medicine , cardiology , myosin , cardiomyopathy , troponin , muscular dystrophy , anatomy , biology , heart failure , physical medicine and rehabilitation , myocardial infarction , biophysics
Hypertrophic cardiomyopathy (HCM) is due to a number of mutations of contractile protein genes such as β‐cardiac myosin, myosin binding protein‐C, and troponin‐T. Unlike troponin‐T, β‐myosin is a constituent of slow skeletal muscle and its mutations generally have a better prognosis. In order to investigate the usefulness of electromyography in detecting skeletal muscle involvement in HCM, 46 patients were examined using both conventional electromyography (EMG) and quantitative electromyography (QEMG) methods. The QEMG involved motor unit potential (MUP) analysis, turns/amplitude (TAA) analysis, and power spectrum analysis of the interference pattern. Using conventional EMG, myopathic findings were demonstrated in 13 patients (28%). Receiver operating characteristic (ROC) analysis of the results of a discriminant function extracted using QEMG values, identified correctly 10 out of 11 normal controls and all 9 myopathic control patients, and displayed a 15% presence of myopathy (7 patients) among the cardiomyopathy group. The duration of MUPs was the most sensitive among the quantitative parameters in differentiating normal from myopathic subjects. Since skeletal muscle involvement may be due to distinct gene mutations, normal and myopathic EMG findings may reflect HCM subpopulations with a different genetic substrate. © 2000 John Wiley & Sons, Inc. Muscle Nerve 23: 1856–1861, 2000